It's been just over a year since Intel unveiled the first six-core consumer processor, the Core i7-980X. Combining all of Intel's then-hottest technologies, it gave both die-hard enthusiasts and professionals who regularly deal in highly threaded apps something to drool over: With a 3.33-GHz clock speed and lots of threads and cache, it redefined "fast" for desktop PCs. But with the advent of the midrange "Sandy Bridge" chips in January, and their technology innovations likely to implemented into Intel's high-end "tick" later in 2011, it was clear the Core i7-980X wouldn't cut it for much longer. Now replacing it at the uppermost extreme of Intel's lineup is the Core i7-990X, which bumps up the clock speed but leaves all of the Core i7-980X's numerous pluses and major minus (its $999 list price) intact.

That means that, in terms of strict technology, there's not a lot of difference between the original processor and this update. Both are based on the 32nm Gulftown core design, the most recent evolution of the 45nm Nehalem microarchitecture that appeared with the first Core i7 chips in late 2008. The biggest change, as mentioned, is that clock speed: It's been raised to 3.45 GHz, with the capability of hitting as much as 3.73 GHz under Turbo Boost (the Core i7-980X's limit there was 3.6 GHz). Otherwise, the number of threads (12, thanks to Hyper-Threading), the amount of cache (12MB), the TDP (130 watts), new AES-NI instructions, the unlocked multiplier for simplified overclocking, the socket requirement (LGA1366), and everything else is identical (and identically exciting). The only real difference is performance.

It's a modest difference, toowhich is exactly what you'd expect in this case. Whereas the Core i7-980X took 3 minutes and 27 seconds in our test applying a dozen complex filters in Adobe Photoshop CS5 ($699 to $999 list, 5 stars), the Core i7-990X trimmed it down to an even 3 minutes 20 seconds. Using Handbrake to convert a video to an iPod-ready format took 75 seconds on the Core i7-980X, but only 72 seconds on the Core i7-990X. The Cinebench R11.5 rendering test returned a score of 8.87 on the Core i7-980X; with the Core i7-990X, we saw 9.23. In our TrueCrypt encryption test, the Core i7-980X rated 280 MBps, the Core i7-990X an even zippier 297 MBps. We saw similarly small increases in our 3DMark 11 and 3DMark Vantage gaming tests (9,332 to 9,591 and 32,129 to 33,382, respectively) and comprehensive Geekbench benchmark (13,083 to 13,586), as well as throughout our more probing AIDA64 and SiSoftware Sandra processor tests.

Comparing to other CPUs revealed starker contrasts in performance: The Sandy Bridge quad-core Core i7-2600K (much cheaper, at $317 list, but at the top of its class), lagged well behind in most tests, but triumphed in one: Photoshop, taking 2 minutes and 57 seconds to plow through the filters. (As Sandy Bridge chips are loaded with technologies for improving everyday media handling, this is not a huge surprise.) AMD's own six-core flagship, the Phenom II X6 1100T ($265 list) offers decent competing value, but is outpaced even by the Core i7-2600K in most circumstances. One thing remains clear: If you want the most in six-core power, you have to go to Intel. (At least for nowwith AMD's new Fusion platform making headroom and the Bulldozer core barreling toward fruition, it's legitimately possible that could change by the end of the year.)

The question is: Do you have to go all the way to the top? Intel's new-ish midrange-enthusiast chip, the Core i7-970 ($885 list, 4 stars), clocks in at 3.2 GHz (3.46 GHz when Turbo Boosted) and also has six cores, 12 threads, and 12MB of cachebut is now priced at just $583. It acquitted itself fairly handsomely on our tests, finishing a solid but seldom-distant third behind the Core i7-990X and the Core i7-980X across the board, but providing a compelling supporting option for those who want to come to the six-core party without a huge financial obligation. And, in fact, for most regular users (and relatively sensible gamers), that's the one we'd most quickly recommend.

But the allure of pure speed is hard to deny, and the Core i7-990X has it in abundance. For those who regularly use highly threaded apps, or whose work demands the best and the fastest, the Core i7-990X is the way to go. Depending on how AMD's and Intel's upcoming releases fare, its technical supremacy in the market could be short lived, but its status as a substantial (if pricey) powerhouse is undoubtedly here to stay for the foreseeable future.

PCMag may earn affiliate commissions from the shopping links included on this page. These commissions do not affect how we test, rate or review products. To find out more, read our complete terms of use.

Matthew Murray got his humble start leading a technology-sensitive life in elementary school, where he struggled to satisfy his ravenous hunger for computers, computer games, and writing book reports in Integer BASIC. He earned his B.A. in Dramatic Writing at Western Washington University, where he also minored in Web design and German. He has been building computers for himself and others for more than 20 years, and he spent several years working in IT and helpdesk capacities before escaping into the far more exciting world...
More »